You can modify the Sawtooth motherboard to take a CPU from a Quicksilver, but this requires removal of one of the IDE connectors and the need to wire a +12V line to the CPU.
Also make sure you get one of the better CPUs with L3 cache, as some of the lower-end ~ 733 - 933Mhz CPUs lack this and can perform about the same as a stock Sawtooth CPU, in some tests.
JB